Tire retreading mold



July 27, 1937. 1.. B. BRbERlNG ET AL 2,088,130

' TIRE RETBEADING MOLD Filed May 14, 1934 3 Sheets-Sheet 1 Fig.3

1 3 \3III E i. g. E. y

INVENTORS. LB. BROER/IYG FE/f/TE ATTOR Y.

y 1937- L. B. BROERING ET AL 2,088,130

TIRE RETBEADINAGV MOLD Filed May 14, 1934 3 Sheets-Sheet 2 /o/ 10a 8s 86 96 \1 INVENTORS, I L. B. BROERING BY Eff Mrs \g '1 ATTORNE.

y 1937. B. BROERING ET AL 30 TIRE RETREADING MOLD Filed May 14, 1934 3 Sh eets-Sheel. 3

INVENTORS. L. B. BROERI/YG Patented July 27, 1937 UNITED- STATES PATENT OFFICE TIRE RETREADING MOLD Lawrence B. Broering and Floyd E. Kite, Los Angeles, Calif., assignors to Kite Mold Company, a corporation of California Application May 14, 1934, Serial No. 725,542

7 Claims.

5 automobile tire.

A specific object, of the invention is to provide an improved mold for curing a tread upon an automobile tire.

Another object of the invention is to provide an improved mountingon an automobile. .tire tread mold.

An additional object of the invention is to provide an improved circulating system for the heat ing fluid of a tire mold.

Another object of the invention is to provide an improved inner ring which closes the cavity in a tire when the latter is being retreaded.

Other objects and the advantages of this invention will be apparent from the following description taken in connection with the following drawings wherein:

Fig. 1 is a side elevation partly in section showing our improved tire retreading mold;

Fig. 2 is a section taken on line.2-2 of Fig. 1;

Fig. 3 is a section taken on line 33 of Fig. 1;

Fig. 4 is a side elevation showing the inner ring;

Fig. 5 is a section through the ring;

Fig. 6 is a side elevation. of. the pneumatic insert; i

Fig. '7 is an end viewof La-modification of our invention;

Fig. 8 is a side elevation of the modification;

Fig. 9 is a section taken on line 9-9 of Fig. 8;

Fig. 10 is a section similarto Fig. 9 showing another type of ring and pneumatic insert;

Fig. 11 is a side elevation of the insert shown in Fig. 10;

Fig. 12 is an end view of a further modification of our invention;

Fig. 13 is a side elevation of the second modification;

Fig. 14 is a section on line l ll4 of Fig. 13 showing the manner in which the circulating system and the upper and lower parts of the mold are connected; and, v

Fig, 15 is a section on line l5-l5 of FigjlB.

Referring to the drawings by reference characters we have shown our invention as embodied in a tire retreading apparatus indicated generally at It. As shown this apparatus includes supporting standards II on which a semi-circular mold member 12 is mounted. The mold member l2 includes a boss I3 in which a pivot pin I4 is mounted to support a second semi-circular mold member I5. Th moldmembersn and I5 are each provided with a cavity l6 which is provided with suitable rib members l1 to form the desired tread. The wall of each of these tire cavities it is formed with an arcuate part l6 arcuate in cross section and with side parts ll extending in straight lines toward the central part it in convergingrelation to each other whereby the cavity is given in cross section substantially the shape of a V having a wide arcuate base, orin other words, the shape ofa U having straight.

sides diverging from the base.

The members l2 and I5 are each also provided with a peripherally extending cavity l8 through which the steam used in vulcanizing is circulated. These cavities l8 extend substantially throughout the width of the mold and entirely across the tread of a tire positioned therein. The members I2 and I5 are provided with bosses l9 and 26, respectively. The boss 20 is provided with a pin 2| on which a fastening member 22 is pivoted. This fastening member is threaded and a nut thereon serves to hold the parts assembled.

A steam supply pipe is shown at 24'. Steam passes from this pipe to a pipe 25 which has a valve 26 secured thereto. A pipe 21 extends from the valve 26 'and this pipe 21 communicates through afitting 28 with the cavity in the lower mold member l2. From this cavity steam passes through a fitting 29 (see Fig. 3) through a valve 30 and through a fitting 3 I into a passageway 32, thence, through a sleeve member 33 into a passageway 34, a fitting 35, a valve 36, a fitting 3'! and the cavity I8 in the upper .mold. The steam then passes through a fitting 33, a flexible hose 39, a pipe 40, a valve and a returncon duit 42.

The sleeve member 33 is secured rigidlyin the passageway 34.and is tapered atits lower end 43 to fit atapering portion at the end of the pas- .sageway 32. A gasket 34' is arranged about the end of the passageway 32 to provide a fluid tight joint. The sleeve member 33 moves upwardly when the mold is parted and the construction is such that when all valves are open steam passes through the circulating system of the mold. After the cure is effected the valve 26 is closed after which the valves 30, 36' and ll are closed and the mold is parted and the cured tire is withdrawn.

In the use of our invention we first place the desired amount of raw rubber stock upon the tire and place the same in the lower mold. An air bag 44 is then insertedin place and a ring indicated generally at 45 is next inserteda The ring 45 includes segmental portions 46 which are hinged in pairs as at 41 and slotted on opposite faces as at 48. Flange members 49 are movably retained in the slots 43 by pins 50 which pass through apertures in the flanges 49. The two pairs of segments are held in alignment by lugs 52 which include set screws 53 engaging apertures 54 in the segmental portions 46.

After the parts are assembled the upper mold I5 is clamped in position by the nut 23, the air bag 44, is inflated, and the valves 26, 30, 36 and 4I are opened. The tire is allowed to cure a predetermined time after which the valves 26, 39, 36 and M are closed, the air bag 44 deflated, the nut 23 released, and the mold member i5 swung about the pin I4 out of the operators way. The air bag 44 and the ring 45 are then removed and the tire is taken from the mold member I2.

The mold members I2 and I5 are similar in cross section and the inner peripheral faces 55 thereof terminate (as shown in Fig. 2) at locations within the periphery of the flanges 49 and substantially midway between the tread and bead of the tire. The flanges are more or less rigid and their extreme ends are spaced from the tire sidewall to form a space, as shown at 56. This construction prevents pinching the tire case when the air bag is inflated and prevent the exertion of any pressure from the air bag to the unconfined side walls of the tire.

A modification of our invention is shown in Figs. '7, 8 and 9. As shown this apparatus comprises supporting standards II having thereon a segmental mold member I2, which is provided with an upwardly facing mold cavity. The standards 'I I have pins i3 mounted thereon and these pins fit apertures in lugs I4 on segmental mold members I5 and I6 which cooperate with the mold member I2 to form a complete mold cavity.

The mold members 12, I5 and I6 are each provided with peripheral cavities I? through which the vulcanizing steam is circulated. The ends of the cavities are closed and in order to secure circulation we provide a steam inlet pipe 18 which is connected by a swivel coupling I9 to a pipe 80 which is connected by a swivel coupling 8| to a pipe 82 which is connected by a swivel coupling 83 to one end of the cavity II, in the mold member I6. The other end of this mold cavity is connected by a fitting 84, hose 85, and fitting 86 with one end of the circulation cavity in the mold member I2. The other end of this circulation cavity is connected by a fitting 87, a hose 88 and a fitting 89 with one end of the circulation cavity in the mold member '55. The other end of this circulation cavity is connected by a swivel fitting 90 with a pipe 9| and this pipe is connected by a swivel fitting 92 with a swivel fitting 93 which is connected to a return pipe 94.

All of the mold members I2, I5 and I6 are similar in cross section and the inner peripheral faces 95 thereof terminate within the periphery of flanges 96 on a ring member 91. This ring member is shown as made of one piece of material and the flange portions are spaced at a slight distance from the wall 98 of the tire. This spacing is indicated at 99, and as the flanges are more or less rigid pressure of the air bag 44 cannot force the flanges against the tire sidewalls so that pinching is prevented.

In Fig. 10 the mold member I00 is similar to the mold members previously described but it is shown as in use with a modified ring I0 I, and an air bag I02, which is semi-cylindrical in cross section. The ring IIlI is shown as of four segments I03, I04, I05 and I06, all hinged together with the end sections I93 and I96 having attaching means IO'I to secure the ring in extended position. The ring II]! has a width less than the distance across the inside of the tire to provide a space I08 and the ring has a diameter greater than the diameter of the inner peripheral faces I09 on the mold members.

In the modification of our invention shown in Figs. 12 to 15, inclusive, a pair of spaced standards I support a lower mold member MI. The standards I20 support a platform I22 on which is arranged a reversible motor I23, a cable drurn I24, is driven through worm gearing I25 by the motor I23. A second mold member I26 includes end portions I2I which are arranged to slide vertically on posts I28, as shown. A cable M9 is secured to the mold member at one end and passes over a pulley I30 and is then wound about the drum I24. When the motor I23 is driven in one direction the mold member I26 is raised and when the motor is driven in the reverse direction the mold member I26 is lowered upon the mold member I2I.

The mold members I2I and I26 are provided with mold cavities similar to those previously described. The upper mold member is provided with a steam cavity I3I while the lower mold member I2I is provided with a steam cavity I32. The mold member I2I is provided with a conduit member I33 which is L-shaped and is fitted at one end with a nipple E34 which is connected by a fitting I35 with a steam supply pipe I 36 which includes a valve I31.

The other end of the conduit I33 is provided with a tapered bore I38 in which a valve member I39 is fixed. This valve member E39 is provided with a plurality of apertures I40 through which steam passes and with a rigid upwardly directed post I4I. Below the valve member I39 we arrange a pair of floating disks I42 which are normally urged against the valve I39 by a spring I43 which engages a shoulder I44 and the construction is such that the valve apertures I40 normally remain closed. The disks I42 are pro vided with aligned holes I45 for the passage of fluid.

The mold member I26 is provided with a downwardly projecting Valve member I46, which is provided with a valve seat I4! for a ball valve I48 which is urged to its seat by a spring I49. The spring I49 is held in place by an annular member I50 through which the steam passes. The valve member I46 is provided with a plural ity of pins I5I which pass through the apertures I40.

In operation when the mold member I26 is lowered upon the mold member I2I the valve member I46 enters the bore I38. The post I4I opens the valve I48 and at the same time the pins I5I move the disks I42 to open the apertures I40. It will thus be seen that when the mold members I2I and I26 are separated the valves are closed, and that when these members are together communication is established between them at one end.

In order to provide communication between the steam cavities at their other ends. the upper mold member I26 is provided with a valve member I52 which fits in the tapered bore I53 of a boss I54 which projects into the steam cavity I 32 in the lower mold member I2I. The valve member I52 is in all respects like the valve member I46 and it coacts with a valve I55 which comprises disks to provide a valve construction and flow control .mold member I26.

means which is similar in all respects to that .described in Fig. 14.

In operation a tire is placed on the lower mold member I 2|, the air bag and ring are then inserted and the motor I23 operated to lower the The air bag is inflated and the valve I3! is then opened and steam passes through the mold member I26, into the mold member IZI and passes from this later mold member through a pipe I56 which includes a valve I57. After the cure is efiected the motor I3! is operated in a reverse direction to lift the mold member I26 and a finished tire is then removed.

From the foregoing description it will be apparent that we have provided a novel tire retreading apparatus which is simple in construction and which is highly efficient in use.

Having thus described our invention, we claim:

1. In a tire retreading apparatus, a base having a segmental mold member fixed thereon, a pair of segmental mold members pivotally mounted for movement towards and from each other, each of said mold members having steam cavities therein, means to connect each end of the steam cavity in the fixed mold member to the adjacent end of the steam cavity in the movable mold members, and means to connect the adjacent ends of the steam cavities in the movable mold members, saidlast mentioned means including pipes pivotally mounted on the movable mold members, a live steam pipe swivelly connected with one of said pipes and an exhaust steam pipe swivelly connected with the other steam pipe.

2. In a tire retreading apparatus, a base having a segmental mold member fixed thereon, a pair of segmental mold members swingably attached thereto, each of said mold members having steam cavities therein, means for connecting the steam cavity of the fixed mold member to the steam cavities of the movable mold members, and means to connect the steam cavities of the movable mold members, said last mentioned means including tubular means pivotally mounted on the movable mold members, a line steam pipe swivelly connected with one of said tubular means and an exhaust pipe swivelly connected with the other of said tubular means.

3. In a tire retreading apparatus, a base having a segmental mold member fixed thereon, a pair of segmental mold members swingably attached thereto, each of said mold members having steam cavities therein, means for connecting the steam cavity of the fixed mold member to the steam cavities of the movable mold members and means for supplying and exhausting steam to said cavities, said last mentioned means including pipes swivelly connecting one of said movable segments to a steam inlet, pipe and pipes swivelly connecting the other of said movable segments to a fluid outlet pipe.

4. In a tire retreading apparatus, a vertical circular mold formed of end opening hinged segments and having its inner face formed with a tirecavity adapted to receive a tire with a thickness of retreading stock applied thereto, each of cross section an arcuate central part and straight side parts merging into the central part in converging relation to each other, the side walls of said mold being relatively short and terminating substantially midway between the tread and bead of the tire, a circular air bag within the tire, and a substantially U-shaped floating rim having its edge portions terminating adjacent the edges of the mold and spaced inwardly therefrom a distance materially greater than the thickness of the side walls of the tire to prevent the exertion of any pressure from the air bag to the side walls of the tire.

5. In a tire retreading apparatus, a full circle mold formed of end opening hinged segments and having its inner face formed with a tire cavity adapted to receive a tire with a thickness or" retreading stock applied thereto, each of said segments having a circumferentially extending steam cavity projecting laterally entirely across the tread of the tire throughout the length of the steam cavity, said tire cavity having in cross section an arcuate central part and straight side parts merging into the central part in converging relation to each other, the side walls of said mold being relatively short and terminating substantially midway between the tread and bead of the tires, pressure means Within the tire for compressing the same against the side walls of the tire cavity, and means adjacent the edges of the mold and spaced inwardly therefrom a distance materially greater than the thickness of the side walls of the tire to prevent the exertion of any pressure from said pressure means to the side walls of the tire.

6. In a tire retreading apparatus, a full circle mold having its inner face formed with a tire cavity adapted to receive a tire with a thickness of retreading stock applied thereto and further having a circumferentially extending steam cavity projecting laterally entirely across the tread of the tire throughout the length of the steam cavity, said tire cavity having in cross section an arcuate central part and straight side parts merging into the central part in converging relation to each other, the side walls of said mold being relatively short and terminating substantially midway between the tread and bead of the tire, pressure means within the tire for compressing the same against the walls of the tire cavity, and means adjacent the edges of the mold to prevent the exertion of any pressure from said pressure means to the side walls of the tire.

'7. In a tire retreading apparatus, a full circle Cal 

